1. Field of the Invention
The present invention relates to an improved locking device for a vehicular folding seat designed for removable attachment thereto of a child seat.
2. Description of the Related Art
In recent years, various types of child seats have been proposed to meet the mandatory requirement that an automotive vehicle seating a small child, such as an infant or schoolchild, should be equipped with a dedicated child seat. The child seat, which is smaller in size than an ordinary seat for adult (so-called xe2x80x9cadult seatxe2x80x9d), is placed on and then securely fixed to the adult seat, such as by fastening the child seat with a seat belt or in accordance with the xe2x80x9cISO-FIXxe2x80x9d (FIXATION) specifications prescribed by the ISO (International Organization for Standardization).
FIG. 10 is a perspective view explanatory of how a child seat is fixed to an adult seat of an automotive vehicle in accordance with the ISO-FIX specifications. The child seat 100 designed in compliance with the ISO-FIX specifications (hereinafter also called an xe2x80x9cISO-FIX child seatxe2x80x9d) includes a pair of left and right lock pieces 101L and 101R extending horizontally rearward from lower end portions of the seat back (in the illustrated example, xe2x80x9cLxe2x80x9d and xe2x80x9cRxe2x80x9d added to reference numerals represent the left and right, respectively, corresponding to left and right arms of a vehicle driver looking ahead from behind a steering wheel). The lock pieces 101L and 101R each has, at its distal end, a U-shaped channel portion 102L or 102R opening rearwardly, and a latch (not shown) is incorporated in each of the channel portions 102L and 102R.
Adult seat 110 designed in compliance with the ISO-FIX specifications (hereinafter also called an xe2x80x9cISO-FIX adult seatxe2x80x9d), on the other hand, includes a seat bottom frame 112 incorporated in a seat base or bottom 11, and a pair of left and right legs 113 L and 113R each extending downwardly from a front end portion of the seat bottom frame 112 and secured at the lower end to a vehicle compartment floor 115 by means of a hinge (only the left hinge 114L associated with the left leg 113L is shown in the drawing). The ISO-FIX adult seat 110 also includes a pair of ISO-FIX seat strikers 116L and 116R projecting upwardly from a rear end portion of the seat bottom frame 112 so that the child seat 100 can be securely attached to the adult seat 110 by means of the ISO-FIX seat strikers 116L and 116R. Namely, the child seat 100 can be fixed to the adult seat 110 by bringing the U-shaped channel portions 102L and 102R into engagement with the ISO-FIX seat strikers 116L and 116R and then locking the U-shaped channel portions 102L and 102R in the engaged state via not-shown latch mechanisms.
FIG. 11 is a perspective view supplementary to FIG. 10, which shows more details of the conventional ISO-FIX adult seat 110. Left and right catchers 120 L and 120R are provided on rear end regions of side portions of the seat bottom frame 112, and latches 121L and 121R are incorporated in or attached to the respective catchers 120 L and 120R. The seat bottom frame 112 is secured to the vehicular floor 115 with the latches 121L and 121R engaged with floor strikers 122L and 122R projecting upwardly from the floor 115. When the adult seat 110 is to be folded into a stowed position, delatching cords 123L and 123R associated with the latches 121L and 121R are pulled rearwardly to disengage the respective latches 121L and 121R from the floor strikers 122L and 122R.
Allowing for removable attachment of the ISO-FIX child seat 100 to the ISO-FIX adult seat 110, the left and right catchers 120 L and 120R must have sufficient mechanical strength or rigidity, and the left and right floor strikers 122L and 122R have to be rigid enough accordingly. However, the catchers 120 L and 120R and floor strikers 122L and 122R with such sufficient rigidity undesirably lead to increased costs.
Further, each time the adult seat 110 is to be folded or flipped up, the left and right delatching cords 123L and 123R have to be pulled as noted above in relation to FIG. 11, which would involve bothersome manual operations. Furthermore, if the left and right delatching cords 123L and 123R are interconnected via a connecting rod so that pulling only one delatching chord can simultaneously disengage the left and right latches 121L and 121R from the floor strikers 122L and 122R, the connecting rod and other elements associated therewith would increase the total number of necessary component parts.
It is accordingly an object of the present invention to provide an improved locking device which is suitable for use in a folding adult seat designed for removable attachment thereto of a child seat and which permits reduction in weight of necessary catchers and strikers and also facilitates operations necessary for folding the adult seat.
In order to accomplish the above-mentioned object, the present invention, in one aspect, provides a locking device for a folding adult seat in an automotive vehicle, which comprises: a first locking mechanism that normally retains a seat base or bottom of the folding seat in a first locked state relative to a floor of the vehicle, and cancels the first locked state of the seat bottom when the seat is to be flipped up or folded into a stowed position; and a second locking mechanism a) that is normally kept in a nonlocking state such that the seat bottom of the adult seat is secured to the vehicle floor by the first locking mechanism alone as long as no child seat is attached to the adult seat, b) that, as a child seat is moved toward and engaged with the adult seat, retains the seat bottom of the adult seat in a second locked state relative to the vehicle floor, and c) that, as the child seat is disengaged from the adult seat, cancels the second locked state, leaving the seat bottom retained only in the first locked state.
When no child seat is attached to the folding adult seat, the adult seat is connected to and locked relative to the vehicle floor by means of the first locking mechanism alone. The first locking mechanism has no direct relation to the attachment of the child seat, i.e. is not directly operated on by the child seat during and after the attachment of the child seat, and thus the first locking mechanism may be constructed to have a relatively small size and weight (and hence relatively low rigidity). When the child seat is attached to the folding adult seat, on the other hand, the seat bottom of the adult seat is locked relative to the vehicle floor not only by the first locking mechanism but also by the second locking mechanism that automatically locks the seat bottom of the adult seat by being operated on (e.g., pressed) by part of the child seat as the child seat is moved toward and engaged with the adult seat. In this condition, the second locking mechanism that is directly operated on (e.g., pressed) by the attached child seat is constructed to have rigidity great enough for performing a primary seat-bottom locking function to lock the seat bottom of the adult seat relative to the vehicle floor, while the first locking mechanism is constructed to have lower rigidity for performing just an auxiliary seat-bottom locking function. Therefore, according to the present invention, the first locking mechanism can be constructed to have a smaller size and weight than the second locking mechanism.
As compared to the conventional locking device which connects and locks the adult seat to the vehicle floor using a pair of left and right locking mechanisms both having relatively great rigidity (hence a great size and weight), the locking device of the present invention can significantly reduce the size and weight of the first locking mechanism while requiring only the second locking mechanism to have a great size and weight for great rigidity. By the reduction in the size and weight of the first locking mechanism, the present invention can reduce the overall weight and cost of the locking device.
Further, the second locking mechanism is normally kept in the nonlocking state such that the seat bottom of the adult seat is secured to the vehicle floor by the first locking mechanism alone as long as no child seat is attached to the adult seat. Thus, with no child seat attached, the adult seat can be readily flipped up or folded by only manipulating the first locking mechanism. Namely, the present invention can significantly facilitate the necessary operations for folding the adult seat, as compared to the conventional locking device where the two locking mechanisms have to be manipulated or shifted to the nonlocking state in order to allow the adult seat to be folded.
Desirably, the second locking mechanism includes a latch pivotable between a locking position where the latch is kept in engagement with a floor striker provided on the floor of the vehicle to thereby retain the second locking mechanism in the locking state and an unlocking position where the latch is kept out of engagement with the floor striker to thereby retain the second locking mechanism in the nonlocking state, and the latch is normally biased to the unlocking position but pressed to the locking position by part of the child seat as the child seat is moved toward and engaged with a seat striker provided on the adult seat.
In a specific form of the invention, the first locking mechanism is disposed on one end of the seat bottom while the second locking mechanism is disposed on an opposite end of the seat bottom. The first locking mechanism that tends to be used more frequently than the second locking mechanism may be positioned near the middle of the vehicle compartment so that it can be accessed easily and manipulated conveniently.